import argparse

import numpy
from numpy import exp, pi
from matplotlib import pyplot


# Style might look a little weird
# It's (almost) a line-by-line transcription of a .m file
def make_check(fname, show_plots=False):
    d = numpy.loadtxt(fname)
    npt = len(d)
    d = d.transpose()

    den = 33
    n2 = int(npt/den)
    dt = 14.0/1320  # us
    n3 = n2*den
    ix = numpy.arange(n3) + 1
    # t = dt*ix

    # mr = d[0][0:n3] + 1j*d[1][0:n3]  # multiplier result
    # st = d[2][0:n3] + 1j*d[3][0:n3]  # state
    # pr = d[4][0:n3]  # probe reflection
    rf = d[5][0:n3]
    # m2 = d[6][0:n3]  # voltage magnitude squared

    lo = exp(-ix*2*pi*1j*7/den)
    rx = rf*lo
    rxr = numpy.reshape(rx, [n2, den])
    rxa = numpy.mean(rxr, 1)
    t2 = dt*den*(numpy.arange(n2)+0.5)

    kx = numpy.nonzero(t2 > 8)
    pp = numpy.polyfit(t2[kx], numpy.angle(rxa[kx]), 1)
    detune = pp[0]/(2*pi)
    print('phase slope %.2f kHz' % (detune*1e3))

    if show_plots:
        pyplot.plot(t2, rxa.real, label='real')
        pyplot.plot(t2, rxa.imag, label='imag')
        pyplot.plot(t2, abs(rxa), label='abs')
        pyplot.legend()
        pyplot.xlabel(u't (\u03bcsec)')
        pyplot.title('cav_mode.v pulse response')
        pyplot.savefig('cav_mode_check1.png')

        pyplot.clf()
        pyplot.plot(t2, numpy.angle(rxa), label='phase simulated')
        ss = 'phase fit, slope %.2f kHz' % (detune*1e3)
        pyplot.plot(t2[kx], numpy.polyval(pp, t2[kx]), label=ss)
        pyplot.legend()
        pyplot.xlabel(u't (\u03bcsec)')
        pyplot.ylabel('radians')
        pyplot.savefig('cav_mode_check2.png')

    mech_freq = 2000000  # pasted from cav_mode_tb.v
    detune_theory = -mech_freq/(2**32*dt)  # XXX negative is ugly
    err = detune/detune_theory-1
    print('err = %g' % err)
    return abs(err) > 0.004


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='Test cav_mode')
    parser.add_argument('-c', '--check', action='store_true', default=True,
                        help='Purely run the check')
    parser.add_argument('-s', '--simulate', action='store_true',
                        help='Show plots based on simulation')
    args = parser.parse_args()
    if make_check('cav_mode.dat', show_plots=args.simulate):
        print('FAIL')
        exit(1)
    else:
        print('PASS')